What is a 4K Wallpaper? 4K may refer to either the 3840 x 2160 or the 4096 x 2160 pixel high definition resolution. 4K refers to a resolution that is four times as high as Full HD (1920 x 1080 pixels), which is the current high definition standard. 720p and 1080i are two more high definition standards that are now in use. Officially, the term "4K" means "Ultra HD" or "Ultra High Definition" for consumer goods, although it may also refer to "4K x 2K," "Quad High Definition," or "2160p" depending on the context.
